Oscillating device activated by blmetallic element and provided with automatic ambient temperature compensating means



Aug. 24, 1954 A, E RE|TZ 2,687,007

OSCILLATING DEVICE ACTIVATED BY BIMETALLIC ELEMENT AND PROVIDED WITHAUTCMATIC AMBIENT TEMPERATURE COMPENSATING MEANS FiledJune 2, 1953 BYE 4ATTOR Y Patented Aug. 24, 1954 2,687,007V osoILLATINGvDEvICE AcTIvATEnBY B1- -METALLIC ELEM WITH AUTOMATI ENT AND PROVIDED C AMBIENT TEMPERA-TURE COMPENSATING MEANS Archie E.`Reitz, Los Angeles, Calif. ApplicationJune 2, 1953, Serial No. 359,189

5 Claims. l

My present invention relates generally to motors, and has particularreference to a motive unit `which generates oscillatory movements as theresult of distortion of a bi-metallic element `whose opposite surfacesare subjected to different temperatures at successive intervals of time.Coordinately, my invention relates to oscillating vdevices in `which thedriving motor is of the character mentioned. Y A general object of theinvention is to improve the efficiency, reliability, and versatility ofa type of motive `unit that affords a simplified and unusuallyinexpensive source of relatively minute motive power suitable for suchuses as the animation of light-weight advertising displays, amusementdevices, and similar items. The type of motor to which the inventionrelates derives its energy from an activator having `a temperatureappreciably diierent from the ambient temperature, the temperaturedifferential being utilized by means of the distortions of aloi-metallic element. This element is of the well-known type whoseopposite surfaces have different temperature coeflicients of expansion.More particularly, motors of this type involve a resilient deectablestrip secured in association with the activator in such a way that oneend oi the strip is anchored at a point of pivotal support while thestrip extends in an adjacent relation to the activator. The stripincludes or is formed of a loi-metallic element adapted to distort uponsubjection to the two different temperatures which are thus afforded.The distortion is effective to initiate a swinging movement of the stripaway from the activator, and it is during this swing that thelai-metallic element is afforded an opportunity to resume its normalshape, so that upon the completion of the return swing the activator isagain effective to distort the bi-metallic element and thereby repeatthe operation.

In the preferred embodiment of the present invention, the source oftemperature diierential is an ordinary electric lamp of relatively lowwattage. The heat generated by such a lamp is quite small but isnevertheless suflicient for the present purpose. Where the motor is tobe used for the animation of advertising displays such as the cardboarddevices commonly employed on store counters and in store windows, theuse of an electric lamp as the source of temperature diierential is ofparticular advantage because it can be utilized at the same time toilluminate the display. It has been found that the heat radiated `bysuch a lamp often warms up the surrounding region to an excessive degreeand varies the ambient temperature gradient to such an extent that thedesired cooling-oit of the bi-inetallic element during the outward swingdoes not occur as quickly and reliably as it should, the smooth andefficient operation of the motor being correspondingly impaired. It is aprincipal object o f the present invention to overcome this diiculty andto provide a novel means for automatically compensating for variationsin the ambient temperature.

In accordance with my invention, an independent bi-metallic member isinterposed between the lamp and the resilient swinging strip, and is sopositioned as to establish contact with the swinging strip and transmitheat to the latter (by conduction) on each return swing. The bi-metallicmember also serves as a barrier to the transmission of radiant heat fromthe lamp to the space in which the movements of the swinging ystrip takeplace. is so constructed as to provide a substantially constant area ofcontactwith the swinging strip under all operating conditions and tomove the contact area away from the heat source inresponse to increasedtemperature thereof to limit the return swing of the strip by acorresponding amount.

The bimetallic member is itself of resilient character and thus servesto afford a resilient abutment for the strip on each return swing of thelatter.

` The preferred way of achieving the objects and advantages of theinvention is illustrated in the accompanying drawing, in which:

Figure 1 is an elevational View of the working parts of an illustrativeoscillating device constructed in accordance with the present invention;

Figure 2 is a view similar to Figure 1 showing the device under theoperating conditions that exist after the lamp has become heated; and

, Figure 3 is a View taken at right angles to Figure 1.

In the device shown, 20 represents an ordinary electric lamp, having arelatively low wattage such as watts or so, mounted in an ordinary lampsocket 2 l. The socket is provided with wires 22 for connection to asource of electric current, and may be secured in any suitable fashion,as by bolt 23, to a supporting bracket :it by means of which the lamp ismounted in appropriate association with a display or other oscillatingdevice in connection with which it is to be used.

The bracket 24 is provided with a substantially In addition, thebi-metallic member rigid upstanding member or bar which extendsalongside of and is spaced from the socket 2|. Secured to the upper endof the bar 25, by bolts 2t or equivalent mounting expedient, is aresilient deiiectable strip which extends upwardly in adjacent relationto the lamp 20. This strip may be constructed in various ways. Itincludes as a part thereof a bi-metallic element so shaped andpositioned that the heat of the lamp is effective to distort it and bysuch distortion to initiate a swinging movement of the strip away fromthe lamp. I have chosen to illustrate the strip Si! as being constitutedalmost entirely of a bi-metal, its lower end being directly secured tothe bar 25. The strip 3E! is so positioned that it normally lies inclose proximity to the lamp 20, and the two metals of which the elementis formed, are arranged with respect to the lamp so that the heat fromthe lamp will distort the element to initiate a swinging movement awayfrom the lamp.

For illustrative purposes I have shown an element 35, intended torepresent part of an advertising display device, secured to the free endof the segment 3|, the latter being secured to the upper end of thestrip Se by rivets 32. The element S5 may be composed of a blank ofcardboard or the like and may have an appropriate cardboard loop orrecess 3S formed cn it by means of which it is frictionally supportedupon the free end of the segment 3l. The element constitutes a loadwhich is so designed and weighted in relation to the shape anddisposition of the deflectable strip 36 on which it is mounted, that anoscillation of substantial mag-- nitude may be achieved. struction, theparts are intended to swing back and forth within the approximate rangeindicated between the dashed line and 'the dot-anddash position shown inFigure 2. More specifically, the center of gravity of the load. is solocated that when the bi-metallic element 3&3 is distorted under theiniiuence of the lamp 2@ the center of gravity moves past the deadcenter axis extending vertically through the point of pivotal support.Of course, the display element may assume various desired congurations,the center of gravity being properly located and adjusted (if necessary)by means of weights (not shown) secured to the element.

In accordance with my invention, there is interposed between the lamp 2Band the swinging strip 3d an independent elongated bi-metallic shield ormember lli which is heat-conductive and which is heated by the lamp, yetopaque to the radiant energy emanating from the lamp. Where the lamp isof the ordinary shape shown, provided with a substantially globularglass filament enclosure, the shield or member il can be convenientlyformed of a strip of bi-metallic material having its lower end securedto the inner face of the bar 25 by the bolts 26. The member lli) extendsupwardly between the lamp 2S and strip il@ and has an intermediateportion il in abutment with the lamp. Adjacent to its upper end, thestrip lll is sharply bent to form a knee 42 projecting toward theelement 3), the free upper end 43 of the member liti being slightlyspaced from the lamp.

When the lamp is turned on, it becomes heated in well-known fashion.This heat is transferred to the bi-metallic shield or member 40, andthrough it to the strip 3G, causing a distortion of the bi-metallicelement 30. The parts are so designed that the distortion of the element30 is eiiective to move the center of gravity In the illustrated con-Iii all)

i' row, as shown in Figure 2.

of the load 35 past the dead center axis, and as this happens the weightof the load amplifies the swinging movement that has been initiated.Depending upon the size, shape, resilience, and other characteristics ofthe deiiectable strip or element 30 and of the load itself, the swingingmovements will reach an extreme position shown in dot-and-dash outlineat which the stress upon the element 3l) is sufficient to impart areturning impulse. As the parts tend to resume their initial positions,the center of gravity returns across the dead center axis and becomeseifective to complete the return swing. In the meantime, the bi-metallicelement 30 has had an opportunity to return, at least partly, to itsinitial undistorted shape, and the process is repeated as the element Stcomes again into contact with the heated member lll).

While the shield or member Il@ serves as a barrier to the transmissionof radiant heat from the lamp to the space in which the movements of thebi-metallic element 3i) take place, and thus normally prevents thisambient region from becoming overheated, this mere shielding action isnot always as effective as may be desired under certain operatingconditions. For example, when the motor is operating within a small,confined space which is not well ventilated, the temperature gradientaway from the lamp may not decrease suiiiciently to provide propercooling for the bi-metallic element 30. Under such circumstances it maybe advantageous to shift the range of oscillation of the swinging stripSil between extreme positions further removed frorn the lamp than theextreme positions of normal operation. In this way the bi-metallicelement is moved outward to a point of lesser temperature and its returnswing limited to a point not quite so close to the lamp.`

To accomplish these ends, the loi-metallic member lil is effective.Under conditions of greater than normal operating temperature, themember lll distorts away from the lamp 2i! so that the knee 2 moves inthe direction of the ar- As the bi-metallic element 3i! establishescontact with the knee i2 on its return swing, the swing iscorrespondingly limited to a position slightly further from the lamp 2tas the temperature of the latter increases.

The bi-metallic member 4t is itself preferably fabricated of resilientdeflectable material which, however, is substantially stiifer than thatof the lai-metallic element 30. This affords a desirable resilientabutment for the swinging strip on each return swing.

An additional feature helping to make the motor self-compensating andcontinuously operative under all possible operating conditions residesin the sharply bent knee l2 of the bimetallic member 515. The knee d2projects t0- ward the bi-metallic element 35i and provides a iinite,substantially linear contact with the element 3S upon each return swing.As the knee l2 is sharply bent, the contact area is substantially thesame regardless of the position of distortion of the member dit. Thatis, the area of contact between the knee 42 and the element 3&3 does notvary appreciably under different conditions of operation, so that theheat conducted between the member 4B and the element 3U on each returnswing is substantially totally dependent on the temperature differentialtherebetween which has been substantially compensated for as describedhereinabove.

From the foregoing, it is seen that the present invention provides, insimple and inexpensive fashion, an automatic ambient temperaturecompensator, adapted to perform eiliciently and reliably under widelydifferent operating conditions.

In general, it will be understood that those skilled in the art will beenabled to modify the details herein described and depicted withoutnecessarily departing from the spirit and scope of the invention. It isintended, therefore, that these details be considered as illustrativeand not in a limiting sense. l

Having thus described my invention what I claim as new and desire tosecure by Letters Patent is:

1. An oscillating device of the kind described,

` comprising an electric lamp, a resilient deilectable strip secured atone end to a point of pivotal support and extending in adjacent relationto said lamp, including as a part thereof a bi-metallic element soAshaped and positioned that the `heat of the lamp is effective todistort it and by such distortion to initiate a swinging movement of thestrip away from the lamp, and a bi-metallic member positioned betweensaid lamp and said strip to provide a barrier to the transmission ofradiant heat from the lamp to the space within which the movement ofsaid strip takes place, said strip establishing contact with and beingheated by said bi-metallic member on each return swing, said bi-metallicmember being itself distorted away from said lamp in response toincreased temperature of the latter to limit the return swing of saidstrip by a corresponding amount.

2. An oscillating device as defined in claim 1, said bi-metallic memberbeing formed with an angular knee portion projecting toward said stripfor contact therewith on the return swing of said strip, said kneeportion providing a relatively small and constant area of contact withsaid strip` regardless of the distortion of said bi-metallic member.

r3. An oscillating device of the kind described, comprising an electriclamp including a substantially globular filament enclosure, a resilientdeilectable strip secured at its lower end to a point of pivotal supportand extending upward therefrom in adjacent relation to said lamp, saidstrip including as a part thereof a bi-metallic element so shaped andpositioned that the heat of the lamp is elfective to distort it and bysuch distortion to initiate a swinging movement of the strip awayfromthe lamp, a load carried by the free end of the strip and having itscenter of gravity so located that as the strip moves under the influenceof said distortion the center of gravity is carried past the dead centeraxis which extends vertically through said point of support, therebyamplifying the swinging movement away from the lamp, and an elongatedbi-metallic member secured at its lower end and extending upward betweensaid lamp and said strip, said member having its intermediate portionabutting said globular lament enclosure and its upper end portion formedwith an angular knee for contact with said strip on the return swing ofthe latter, said bimetallic member being distorted to move the angularknee away from the lamp in response to increased temperature of thelatter, to limit the return swing of the strip by a correspondingamount.

4. An oscillating device as defined in claim 3, wherein said kneecomprises a sharply bent portion of said bi-metallic member adapted tomake line contact with said strip regardless of the distortion of saidmember.

5. An oscillating device as dened in claim 3, wherein said bi-metallicmember is itself fabricated of resilient deflectable material to afforda resilient abutment for said strip on each return swing.

References Cited in the le of this patent UNITED STATES PATENTS NumberName Date 2,382,928 Whitney et al Aug., 14, 1945 2,561,217 Muir July 17,1951

